Keyboard ESD Protection via Membrane Circuit Segmentation
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Solution Overview
Problem
Existing key structures face challenges in effectively conducting static electricity to ground without increasing manufacturing complexity and circuit board thickness, as existing electrostatic discharge protection configurations often overlap with spacer layers and require additional grounding arms.
Innovation Solution
A key structure with a membrane circuit board featuring a three-layer configuration, including a first and second membrane layer with conductive layers and a spacer layer, where the electrostatic protection structure is positioned at the inner edge or surrounding the openings of the membrane layers, allowing static current to flow through conductive layers to ground without overlapping with the spacer layer, reducing the need for additional grounding arms and minimizing circuit board thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrostatic discharge protection circuit pattern is disposed in an area overlapped with the spacer layer, then the ESD protection function is achieved, but the thickness of the membrane circuit board increases
Solution Approach 1:
The patent transitions from a three-layer membrane structure (with ESD circuit overlapping spacer layer) to a two-layer membrane structure where the ESD protection circuit is formed directly on the front surface of the membrane circuit board. This dimensional reorganization eliminates the need for the ESD circuit to occupy space within the spacer layer, thereby reducing overall board thickness while maintaining ESD protection functionality.
2Reliability
If a grounding arm is additionally configured to conduct static current to ground, then the electrostatic discharge protection is enhanced, but the complexity of manufacturing the key structure increases
Solution Approach 1:
The patent integrates the ESD protection circuit directly into the membrane circuit board structure by forming conductive patterns on the front surface. This merges the ESD protection function with the existing circuit board infrastructure, eliminating the need for separate grounding arms and reducing manufacturing complexity while maintaining effective static current conduction to ground.
3Reliability
If the electrostatic discharge protection circuit pattern overlaps with the spacer layer, then the ESD protection is provided, but the configuration of the key switch circuit is influenced
Solution Approach 1:
The patent segments the ESD protection function from the spacer layer region by forming the ESD protection circuit on the front surface of the membrane circuit board. This spatial segmentation allows the key switch circuit to be configured independently without interference from the ESD protection circuit, while both functions coexist effectively within the same structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables rapid and effective static electricity discharge to ground, simplifying manufacturing processes and reducing the thickness of the circuit board, thereby enhancing manufacturing efficiency and product yield while preventing damage to electronic elements.
Implementation Method 1
an electrostatic protection structure, including: a first conductive layer, formed on a first surface of the first membrane layer; a second conductive layer, formed between the second surface of the first membrane layer and the third surface of the second membrane layer; and a third conductive layer, formed on a fourth surface of the second membrane layer
Data Source
AI summary
The present invention provides a key structure with electrostatic discharge protection, including a key cap; a metal support panel; a support element, connecting the key cap and the metal support panel and capable of guiding the key cap to move up and down relative to the metal support panel; and a membrane circuit board, disposed on the metal support panel. The membrane circuit board includes: a first membrane layer, having a first surface and a second surface; a second membrane layer, having a third surface and a fourth surface; and an electrostatic protection structure, including: a first conductive layer, formed on a first surface of the first membrane layer; a second conductive layer, formed between the second surface of the first membrane layer and the third surface of the second membrane layer; and a third conductive layer, formed on the fourth surface of the second membrane layer.